Session 5 - Open Pit Production Blasting Within 500 Feet of Gas Transmission Lines
(Room Capitol Ballroom 1-4; Fourth Floor)
25 Jan 20
1:10 PM
-
2:00 PM
In December of 2016, the Lafarge Holcim Portland Plant located in Florence CO was faced with the challenge of conducting open pit production blasting on three (3) Benches, adjacent to active gas transmission lines that passed directly through their permit and along some Eastern and Northern extents of the mining area. Up to the time of the project, the pipeline owner limited mining by blasting to within 500 ft of the pipeline. Mining in 2016 was fast approaching the 500 ft distance, a blast plan was developed by mine management and the blasting contractor to advance closer to pipeline, hopefully to within 100 ft, with no damage at the gas pipe line, surrounding infrastructure, and maximizing limestone reserves. This paper presents a practical case study of the progress made in the project from April 2017 thru April 2019. It presents: the 3rd party consultant’s initial recommendations, the blast plan built around those recommendations, actual blast details (drill hole diameter, pattern, explosive loading & timing), seismograph monitoring and their results, linear regression analysis of the seismograph results, and current progress of the project as of the writing of the paper. Blasting progress during the project period covered by this paper has the OBI bench now within 165 ft of the pipeline along over 600 ft of the pipeline length. The OBII bench within 290 ft of the pipeline along the same length and the Limestone bench just within 500 ft. The results achieved to date indicate strongly that mining of: the OBI bench to within 150 ft horizontal distance of the pipeline; the OBII to within 175 ft horizontal distance of the pipeline; and the Limestone bench to within 200 ft of the pipeline, are all possible without damage to the pipeline.